Internal combustion engines for motor vehicles are known which include a hydraulic system for performing work in addition to lubrication. This work can be used to activate/deactivate cylinders of an internal combustion engine to conserve fuel. Such a hydraulic valve lifter activation/deactivation system can include a hydraulic control valve in a valve housing mechanically connected to a separate solenoid. The solenoid includes a solenoid coil bobbin on which a wire coil is wound and an armature that moves the control valve in response to an input signal (coil electrical current signal) to the wire coil to control hydraulic pressure in the valve lifter oil control gallery. A separate check valve assembly is mounted in a fluid exhaust passage (vent-to-sump) in the engine block or cylinder head and functions to maintain oil pressure in the oil control gallery at a preselected minimum value. Such engine oil control solenoids comprise numerous components which must be assembled together and are known to suffer from hydraulic fluid (oil) leakage through various paths around the solenoid housing. An object of the present invention is to provide an improved engine oil solenoid control valve.